Posterior Pseudo-Lenticonus Sign in a Patient with Nipple Cone Keratoconus.

PURPOSE: To describe a previously unreported posterior pseudo-lenticonus sign in a patient with nipple cone keratoconus (KC). CASE REPORT: A 32-year-old female presented with complaints of right eye visual acuity loss. Although she was initially diagnosed with posterior lenticonus, the additional clinical evaluation revealed no true lenticonus. The corneal topography revealed a central nipple cone KC, and the crystalline lend finding was consistent with a pseudo-lenticonus. CONCLUSION: Due to inadvertent visual effects, nipple cone KC may resemble posterior lenticonus.

Customized Stromal Lenticule Implantation for Keratoconus.

PURPOSE: To investigate the potential benefit of keratoconus surgery using customized corneal stromal donor lenticules obtained from myopic small incision lenticule extraction (SMILE) surgery by femtosecond laser. METHODS: In this prospective, consecutive, non-comparative series of cases, 22 lenticules were obtained from 22 myopic patients who had SMILE with a lenticule central thickness of greater than 110 µm. The lenticules were implanted in 22 eyes with advanced keratoconus. The lenticules were customized for the purpose of the implantation with either a simple necklace or necklace-with-ring shape (compound form) depending on the corneal thickness and corneal topography configuration of the implanted keratoconic eyes. The lenticules were implanted into a 9.5-mm corneal lamellar pocket created by the femtosecond laser. Changes in densitometry, thickness, confocal microscopy, corrected distance visual acuity (CDVA), and endothelial cell density were investigated. RESULTS: Intrastromal lenticule implantation was successfully performed in all cases without any complication. Corneal thickness showed a mean enhancement of 100.4 µm at the thinnest point. On biomicroscopy, all corneas were clear at 1 year postoperatively and there was a significant improvement in corneal densitometry during the entire follow-up period. Confocal biomicroscopy showed collagen reactivation without any inflammatory features caused by the implanted fresh lenticules. CDVA improved from 0.70 to 0.49 logMAR (P = .001) and keratometry decreased from 54.68 ± 2.77 to 51.95 ± 2.21 diopters (P = .006). CONCLUSIONS: Customized SMILE lenticule implantation by femtosecond laser proved to be feasible, resulting in an improvement in vision, topography, and refraction in the implanted eyes. [J Refract Surg. 2020;36(12):786-794.].

Comparison of Toric Implantable Collamer Lens and Toric Artiflex Phakic IOLs in Terms of Visual Outcome: a Paired Contralateral Eye Study.

PURPOSE: This study sought to compare the postoperative visual outcomes of toric implantable collamer lens (T-ICL) with toric Artiflex (T-Artiflex) lenses. DESIGN: Alternating treatment, contralateral eye matched clinical study. METHODS: This study compared 82 eyes of 41 patients with T-ICL lenses in one eye and toric Artiflex implantation in the contralateral eye to correct myopic astigmatism. Safety, efficacy, predictability, astigmatic vector changes, contrast sensitivity, endothelial cell count, and possible adverse events were assessed at least 12 months postoperatively. RESULTS: After a mean follow-up of 12 months, the safety index was mean 1.40 ± 0.70 in the T-ICL group and 1.20 ± 0.21 in the T-Artiflex group. Furthermore, their mean efficacy indexes were 1.24 ± 0.42 and 1.08 ± 0.23, respectively (P = .029). A total of 39 eyes (95%) in the T-ICL group and 41 eyes (100%) in the T-Artiflex group were within ±1.00 diopter (D) of emmetropia and 33 eyes (80%) and 34 eyes (83%) were within ±0.5 D of emmetropia, respectively. Vector analysis revealed mean index of success as large as 0.25 ± 0.22 in the T-ICL group and 0.24 ± 0.15 in the T-Artiflex group. Postoperative contrast sensitivities were equal in both groups under mesopic conditions for any given spatial frequency. There was an endothelial loss of 2.18% and 1.95% in the T-ICL and T-Artiflex groups, respectively. There were no significant complications in any of the groups. CONCLUSIONS: Both lenses showed promising results in terms of safety, efficacy, and predictability for correction of myopic astigmatism. As shown in this paired-eye study, most outcomes were almost identical, and neither of these lenses were clinically superior to the other.

A model for predicting sulcus-to-sulcus diameter in posterior chamber phakic intraocular lens candidates: correlation between ocular biometric parameters.

PURPOSE: The aim of this study was to determine the correlation between ocular biometric parameters and sulcus-to-sulcus (STS) diameter. METHODS: This was a cross-sectional study of preoperative ocular biometry data of patients who were candidates for phakic intraocular lens (IOL) surgery. Subjects underwent ocular biometry analysis, including refraction error evaluation using an autorefractor and Orbscan topography for white-to-white (WTW) corneal diameter and measurement. Pentacam was used to perform WTW corneal diameter and measurements of minimum and maximum keratometry (K). Measurements of STS and angle-to-angle (ATA) were obtained using a 50-MHz B-mode ultrasound device. Anterior optical coherence tomography was performed for anterior chamber depth measurement. Pearson's correlation test and stepwise linear regression analysis were used to find a model to predict STS. RESULTS: Fifty-eight eyes of 58 patients were enrolled. Mean age ± standard deviation of sample was 28.95 ± 6.04 years. The Pearson's correlation coefficient between STS with WTW, ATA, mean K was 0.383, 0.492, and - 0.353, respectively, which was statistically significant (all P < 0.001). Using stepwise linear regression analysis, there is a statistically significant association between STS with WTW (P = 0.011) and mean K (P = 0.025). The standardized coefficient was 0.323 and - 0.284 for WTW and mean K, respectively. The stepwise linear regression analysis equation was: (STS = 9.549 + 0.518 WTW - 0.083 mean K). CONCLUSION: Based on our result, given the correlation of STS with WTW and mean K and potential of direct and essay measurement of WTW and mean K, it seems that current IOL sizing protocols could be estimating with WTW and mean K.

Comparison of densitometric profile after deep lamellar keratoplasty with two different techniques for treatment of keratoconus.

PURPOSE: To compare densitometric outcome of two techniques of deep lamellar keratoplasty using Pentacam HR corneal densitometry software. METHODS: Postoperative outcomes of 31 patients with big bubble (BB) and 28 patients with Melles (M) surgery for the treatment of keratoconus were evaluated. Data were gathered at least 3 months after the removal of all sutures including demographic data, uncorrected distance visual acuity (UCDVA), best spectacle-corrected visual acuity (BSCVA), refraction and endothelial cell count. Moreover, the Scheimpflug images were taken by Pentacam® HR to assess keratometric profile, densitometric outcomes in different depths and zones of the cornea and central corneal thickness. Anterior segment OCT was performed in ten cases of M group. RESULTS: Thirty-one eyes with BB and 27 eyes M surgery were enrolled. Comparison of densitometric profile between groups revealed no statistical significance in zone 0-2 mm, zone 2-6 mm and zone 10-12 mm in all depths (all P values > 0.05). Zone 6-10 mm of M group had lower densitometric readings (more transparent) in anterior, central and posterior layers of the cornea in comparison with BB group (all P < 0.05). Also no statistical difference was found in UCDVA, BSCVA, spherical or cylindrical refractive error, and spherical equivalent, keratometric readings, endothelial cell count and central corneal thickness in two groups (all P values > 0.05). CONCLUSION: Densitometric profiles were identical in both methods in visually important zones so as visual and refractive outcomes.

Topography-guided transepithelial photorefractive keratectomy to correct irregular refractive errors after radial keratotomy.

PURPOSE: To evaluate the efficacy and safety of topography-guided transepithelial photorefractive keratectomy (PRK) in a group of patients with post-radial keratotomy (RK) showing irregular corneas. SETTING: Feiz University Hospital, Isfahan, Iran. DESIGN: Prospective case series. METHODS: Consecutive patients who had irregular astigmatism after RK with stable refraction and topography for at least 1 year were recruited. All eyes had excimer laser topography-guided single-step transepithelial PRK. The efficacy, safety, predictability, and corneal wavefront aberration changes were assessed 6 months after the surgery. Vector analysis was performed using the Alpins method to evaluate the astigmatic treatment. RESULTS: Twenty-two patients (22 eyes) were enrolled. The patients' ages ranged from 37 to 61 years (45.77 years ± 4.9 [SD]); there were 12 men (54.54%) and 10 women (45.46%). Uncorrected distance visual acuity significantly improved after 6 months of treatment (0.45 ± 0.19 logarithm of the minimum angle of resolution [logMAR] preoperatively and 0.25 ± 0.19 logMAR after 6 months) (P < .001). Moreover, the corrected distance visual acuity significantly improved at the end of the study (0.14 ± 0.13 logMAR preoperatively and 0.09 ± 0.11 logMAR after 6 months) (P = .01). Furthermore, the aberrometric values were significantly reduced at the 6-month visit (P < .001). The mean of the surgically induced astigmatism was 2.15 ± 1.44 diopters. No significant complication was observed. CONCLUSION: Topography-guided single-step transepithelial PRK is a safe and effective method for treating the irregular refractive errors in post-RK patients.

Effect of iris registration on outcomes of FEMTOLASIK for myopia and myopic astigmatism.

PURPOSE: To compare the visual and refractive outcomes after FEMTOLASIK with and without iris registration. METHODS: In this randomized, prospective, comparative, contralateral eye study, 118 eyes of 59 patients with myopia and myopic astigmatism underwent LASIK using the Femto LDV femtosecond laser (160 µm) and the MEL80 with or without iris registration. For each patient, iris registration FEMTOLASIK was performed on one eye and non-iris registration FEMTOLASIK was performed on the other eye, assigned at random. Patients were evaluated before and 12 months. Uncorrected visual acuity, best-corrected visual acuity, manifest refraction, contrast sensitivity, and higher-order aberrations (HOAs) were evaluated. RESULTS: At 12 months, the mean UDVA was 0.002 ± 0.07 logMAR (20/19) in iris registration eyes and 0.00 ± 0.06 logMAR (20/24) in non-iris registration eyes (P = 0.9). 61% of iris registration eyes and 71.2% of non-iris registration eyes achieved a UDVA of 20/20 or better (P = 0.31); 98.3% of eyes with the iris registration FEMTOLASIK and 94.9% with the non-iris registration FEMTOLASIK were within ±0.50 D from emmetropia (P = 0.71). No statistically significant difference was found in postoperative contrast sensitivity between groups at 3, 6, 12, or 18 cycles/degree (P > 0.05). There was significant increase in total HOA root mean square in two groups. The mean error magnitude of surgically induced astigmatism 12 months postoperatively was -0.33 in iris registration eyes and -0.24 in the non-iris registration eyes (P = 0.36). CONCLUSIONS: FEMTOLASIK with and without iris registration provides similar results in myopic and myopic astigmatism patients.

Comparison of Sub-Bowman Keratoplasty Laser In situ Keratomileusis Flap Properties between Microkeratome and Femtosecond Laser.

BACKGROUND: Since thin and high-quality flaps produce more satisfactory surgical outcomes, flaps created by mechanical microkeratomes are more economical as compared with femtosecond lasers, and no Iranian study has concentrated laser in situ keratomileusis (LASIK) flap peculiarities between Moria Sub-Bowman keratoplasty (SBK) microkeratomes and LDV femtoseconds, the present study compares and contrasts them. MATERIALS AND METHODS: This cross-sectional study was done on all patients who underwent LASIK surgery 1-month before this study. Thirty eyes were divided into per group. Flaps in the first group and second group were created, respectively, using Moria SBK microkeratome and LDV femtosecond laser. The other stages of LASIK were done equally in both groups. One month after surgery, the thickness of flaps was measured by anterior segment optical coherence tomography in five regions of flaps. Corneal anterior density was calculated and recorded 1-month after surgery using pentacam and by employing optical densitometry in a distance in the limit range of 0-6 mm from cornea center. Densitometry measurements were obtained and expressed in standardized grayscale units (GSUs). RESULTS: Postsurgery densitometry results reveal that anterior densities of cornea in limit range of 0-2 mm in groups of LDV femtosecond laser and Moria microkeratome are 21.35 ± 0.87 GSU and 22.85 ± 1.25 GSU, respectively. Accordingly, these two groups are significantly different in this regard (P < 0.001). Moreover, anterior densities of the cornea in the limit range of 2-6 mm in these groups are 19.66 ± 0.99 GSU and 20.73 ± 1.24 GSU, respectively. Accordingly, these two groups are significantly different in this regard (P = 0.04). There is a lower mean of flap thickness in the case of LDV femtosecond laser. CONCLUSION: Femtosecond laser method is greatly preferred as compared with Moria microkeratome because of greater homogeneity in flap thickness, smaller thickness, and lower density in optical zone.

Toric Intraocular Lens for Astigmatism Correction in Cataract Patients.

BACKGROUND: To assess the clinical consequences of AcrySof toric intraocular lens (IOL) and Hoya toric IOL implantation to correct preexisting corneal astigmatism in patients undergoing cataract surgery. MATERIALS AND METHODS: In this study, we examined 55 eyes of 45 patients with at least 1.00 D corneal astigmatism who were scheduled for cataract surgery. After phacoemulsification, toric IOL was inserted and axis was aligned. We observed the patients, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry, manifest refraction, and IOL axis alignment 6 months after surgery. RESULTS: After 6 months, the UDVA was 0.17 ± 0.17 logMAR in the AcrySof group and 0.17 ± 0.18 logMar in the Hoya group. More than 78% of eyes in the AcrySof group and 80% of eyes in the Hoya toric IOL achieved a UDVA of 20/40 or better. In the AcrySof group, the mean preoperative corneal astigmatism was 2.73 ± 0.92 D. The mean postoperative refractive astigmatism was 0.84 ± 0.63 D. In the Hoya group, the preoperative corneal astigmatism was 2.58 ± 0.76 D and the postoperative refractive astigmatism was 0.87 ± 0.66 D (P < 0.05). The mean AcrySof IOL axis rotation was 1.88° ± 3.05°. In the Hoya group, the mean axis rotation was 1.53° ± 3.66°. All changes in visual and refractive data before and after surgery were statistically significant (P < 0.05). There was no significant difference between the two groups regarding refractive and visual outcome after surgery (P > 0.05 for all). CONCLUSION: Implantation of AcrySof toric IOL and Hoya toric IOL was an effective way to correct preexisting corneal astigmatism in cataract surgery.

Comparing aspheric ablation profile with standard corneal ablation for correction of myopia and myopic astigmatism, a contralateral eye study.

The purpose of this study is to compare visual outcomes of myopic refractive surgery, using tissue saving (TS), a standard ablation profile by a Technolas 217z100, and aberration smart ablation (ASA), an aspheric algorithm by a MEL 80 excimer laser in two eyes of one patient. In this prospective interventional paired-eye controlled study, a total of 100 eyes of 50 participants with myopia with or without astigmatism underwent thin-flap Femto-LASIK, using a Femto LDV femtosecond laser (Ziemer Ophthalmic Systems AG, Port, Switzerland). For each patient, one eye was randomly treated with tissue-saving algorithm (TS group) by the Technolas 217z100 excimer laser and the other eye was treated with optimized smart ablation profile (ASA group) by the MEL 80 excimer laser. Outcome measures were uncorrected distance visual acuities (UDVAs), corrected distance visual acuities (CDVAs), manifest refraction, higher-order aberrations (HOAs), contrast sensitivity, and patient satisfaction 12 months after surgery. At 12 months postoperative, "45 subjects returned with mean" UDVA was - 0.02 ± 0.08 Logarithm of mean angle of resolution (LogMAR) for TS group and - 0.02 ± 0.09 LogMAR for ASA group (P = 0.91). Of the TS eyes, 42/45 (93.3%) and 32/45 (71.1%) were within ± 0.5 D and ± 0.25 D of target refraction, respectively, and of the ASA eyes, 41/45 (91.1%) and 30/45 (66.6%) were within ± 0.5 D and ± 0.25 D of target refraction, respectively. No statistically significant differences were observed between groups in HOAs changes and contrast sensitivity function. Aspheric and non-aspheric LASIKs using the two different excimer lasers provide similar results in myopic and myopic astigmatism patients.

Photorefractive keratectomy in the management of postradial keratotomy hyperopia and astigmatism.

BACKGROUND: The aim of this study is to evaluate the results of photorefractive keratectomy (PRK) in the management of postoperative hyperopia and astigmatism in patients with history of radial keratotomy (RK). MATERIALS AND METHODS: This prospective nonrandomized noncomparative interventional case series enrolled consecutive eyes treated with PRK after RK. In cases, in which (1) wavefront (WF) scan was undetectable during primary examinations; and/or, (2) WF data were not transferable to the excimer laser device, patients were treated with the tissue-saving (TS) mode. Patients with detectable/transferable WF were assigned to WF-guided advanced personalized treatment (APT). RESULTS: Thirty-two and 47 eyes were managed by APT and TS modes, respectively. Pooled analysis of both APT and TS groups showed improvement in uncorrected distant visual acuity and corrected distant visual acuity. The amount of sphere, cylinder, corneal cylinder, spherical equivalent, defocus equivalent, and total aberration showed improvement as well. CONCLUSION: PRK seems to bring favorable outcome and safety profile in the management of post-RK hyperopia and astigmatism. It is crucial for practitioners to warn their patients about the fact that they may still have progressive refractive instability regardless of their choice on the laser method of vision correction.

Comparative analysis of the visual performance after implantation of the toric implantable collamer lens in stable keratoconus: a 4-year follow-up after sequential procedure (CXL+TICL implantation).

AIMS: To report on 4-year postoperative visual performance with the toric implantable collamer lens (TICL) for stable keratoconus after sequential procedure (corneal collagen crosslinking plus TICL implantation). METHODS: Forty eyes of 24 patients with stable keratoconus with myopia between 0.00 and -18.00 dioptres (D) and astigmatism between 1.25 and 8.00 D were evaluated in this prospective interventional study (https://clinicaltrials.gov/ct2/show/NCT02833649). We evaluated refraction, visual outcomes, astigmatic changes analysed by Alpins vector, contrast sensitivity, aberrometry, modulation transfer functions (MTFs), defocus curve, and operative and postoperative complications. RESULTS: At 4-year follow-up, 45% had 20/20 vision or better and 100% had 20/40 or better uncorrected visual acuity (UCVA). Vector analysis of refractive astigmatism shows that the surgically induced astigmatism (SIA) (3.20±1.46 D) was not significantly different from the target induced astigmatism (TIA) (3.14±1.42 D) (p=0.620). At 4 years postoperatively, none of the eyes showed a decrease in UCVA, in contrast to 24 eyes in which UCVA was increased by ≥1 lines, with contrast sensitivity and improvement in total aberrations and MTF value at 5 per degree (*p=0.004) after TICL implantation. The cumulative 4-year corneal endothelial cell loss was ≤5%. No patients reported dissatisfaction. At the end of follow-up, the vault was 658±54.33m (range, 500-711) and the intraocular pressure was 11.7±2.08 mm Hg. Occurrences of glare and night-driving troubles diminished after TICL surgery. CONCLUSION: The results from this standardised clinical investigation support TICL implantation from clinical and optical viewpoints in patients with stable keratoconus. TRIAL REGISTRATION NUMBER: NCT02833649, Pre-results.

Photorefractive keratectomy for patients with preoperative low Schirmer test value.

PURPOSE: To compare dry eye signs and symptoms between patients with preoperative low and normal Schirmer test after Photorefractive keratectomy (PRK). METHODS: In this prospective, nonrandomized, comparative case series, 76 eyes of 76 patients were preoperatively categorized into two groups according to selected criteria for characterization of tear film status: the low Schirmer test value (STV) group and the normal STV group. For the tear function assessment, we performed a Schirmer test with and without anesthesia, tear break-up time (TBUT) test, and measurement dry eye symptoms using the Farsi translation of Ocular Surface Disease Index (OSDI) questionnaire pre- and 3 months post-operation. RESULTS: Postoperatively, the Schirmer and TBUT values were significantly lower in both groups than preoperatively (all p < 0.05). Deterioration in tear secretion was significantly greater in the low STV group (p = 0.012), but tear stability was more compromised in the normal STV group (p = 0.021). The changes in OSDI score were not significant between the two groups. CONCLUSION: These results demonstrated that tear function deteriorates after PRK. Therefore, patients with low preoperative Schirmer test values should be thoroughly assessed for dry eye before proceeding with refractive surgery to eliminate postoperative complication.

Evaluation of corneal higher order aberrations in normal topographic patterns.

PURPOSE: This study reports the characteristics of corneal higher order aberrations (HOAs) in eyes with normal topographic pattern using the Pentacam scheimpflug system. METHODS: In this prospective, observational, comparative study, 165 eyes of 97 patients separated into five groups based on corneal topographic patterns were enrolled. All eyes received a comprehensive ophthalmologic examination including corneal tomographic analysis with the Pentacam system. Keratometry, corneal cylinder, and corneal aberrometric data were recorded and analyzed. Root mean square values (RMS) were calculated for corneal HOAs up to the 6th order, total coma, total trefoil, total spherical aberration, total tetrafoil, and higher order astigmatism. Evaluation of these data to discriminate between the five groups was assessed using the analysis of variance test by Generalized Estimation Equation Linear Model. RESULTS: Corneal HOAs were found to be significantly higher for Asymmetric Bow Tie and Irregular groups than other groups (p = <0.001). RMS of total coma aberration ([Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]) were significantly greater in the Asymmetric Bow Tie pattern than others, and RMS of total Spherical aberration ([Formula: see text], [Formula: see text]) was significantly higher in the Irregular pattern than other groups (p = <0.001). The results of our study demonstrate that a tendency toward significant higher values of trefoil, tetrafoil, and higher order astigmatism in Irregular pattern (all p < 0.05). Significantly higher amounts of 3rd order RMS in Asymmetric Bow Tie group and 4th to 6th order RMS in Irregular pattern group were other outcomes of our study (p = <0.001). CONCLUSIONS: Based on results in this study, there were a good correlation between corneal topographic pattern and corneal HOAs in normal eyes. These results indicate that the corneal HOAs values are largely determined by the topographic patterns. A larger sample size would perhaps have been beneficial to yield in more accurate outcomes.

Evaluation of the outcomes of corneal collagen cross-linking in progressive keratoconic eyes.

BACKGROUND: Corneal collagen cross-linking (CXL) is gaining popularity as a treatment in arresting the progression of keratoconus. It is a relatively new therapy using ultraviolet-A (UVA) with a photosensitizer to increase corneal stiffness. The purpose of this study was to evaluate visual, keratometric and topographic outcomes after corneal CXL in progressive keratoconic eyes. MATERIALS AND METHODS: In this prospective nonrandomized clinical study, 140 eyes of 110 patients with progressive keratoconus were treated by combined riboflavin/UVA CXL. Mean sphere, mean cylinder uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractive spherical equivalent, corneal topography, pachymetry, and endothelial cell morphology were examined preoperatively and 12-24 months postoperatively. RESULTS: The preoperative mean sphere was -3.33 ± 3.13 diopter (D) and decreased to -3.09 ± 3.09 D (P = 0.007). The preoperative mean cylinder was -4.05 ± 2.29 D and changed to -3.79 ± 2.23 D (P = 0.011). UDVA changed from 0.95 ± 0.64 logarithm of the minimum angle of resolution (logMAR) to 0.85 ± 0.59 logMAR (P = 0.003). Thirty-five eyes (25%) gained one or more lines of preoperative UDVA, 87 eyes (62.1%) did not change and 18 eyes (12.8%) lost one or more lines of the preoperative UDVA. CDVA in 80% of the patients remained stable (no lines lost). Statistical analysis of keratometry, pachymetry, and endothelial cell count did not show the significant difference after surgery. CONCLUSION: Our study showed improvement in visual and refractive results of the corneal CXL and confirmed that CXL is the safe and effective procedure.

Evaluation of corneal thickness alterations during menstrual cycle in productive age women.

PURPOSE: To determine the change in corneal thickness through different phases of menstrual cycle in women who are in their productive age. MATERIALS AND METHODS: Fifty healthy women with normal past medical history were enrolled in this prospective study. Central corneal thickness was measured with ultrasound pachymeter three times during a menstrual cycle: Beginning of the cycle (days 1-3), ovulation time, and at the end of cycle (days 27-32). We confirmed ovulation time with determining a peak in luteinizing hormone in urine. To avoid the diurnal variation of the corneal thickness which is well recognized, we checked all our subjects at 10 in the morning. RESULTS: In days 1 to 3 of menstruation, mean corneal thickness was 541.40 ± 11.36 and 540.82 ± 11.70 microns for left and right eyes respectively. At ovulation time the mean thickness changed to 556.50 ± 7.11 and 555.98 ± 7.26 microns for left and right eyes respectively, and at the end of the cycle, the corneal thickness turned in to 536.38 ± 12.83 and 535.48 ± 13.08 microns for left and right eyes respectively. The difference of corneal thickness was statistically significant relating to the different stages of menstrual cycle. CONCLUSION: The thickest cornea during the menstruation cycle is achieved at the ovulation time and the thinnest at the end of the cycle and this should be taken in to account whilst plan to do a corneal refractive surgery.

Refractive and Aberration Outcomes after Customized Photorefractive Keratectomy in Comparison with Customized Femtosecond Laser.

To compare the refractive and visual outcomes and higher order aberrations in patients with low to moderate myopia who underwent customized photorefractive keratectomy (PRK) or femtosecond laser in situ keratomileusis (Femto-LASIK) this research performed. This study includes data of 120 consecutive eyes of 60 patients with myopia between -3.00 D and -7.00 D with or without astigmatism in two surgery groups: PRK and Femto-LASIK. Refractive, visual, and aberration outcomes of the two methods of surgery were compared after 6 months of follow-up. After six months of follow-up, sphere and cylinder were found significantly decreased and there was no statistically significant difference between the two groups. The mean of uncorrected distance visual acuity in LogMar format for the PRK and Femto-LASIK groups was -0.03±0.07 and -0.01±0.08, respectively, which was not significantly different between the two groups. Higher orders and spherical aberrations increased in both groups significantly, while total aberrations decreased in both groups. After surgery, no differences were observed between the two groups in the amount of aberrations. In conclusion, Both PRK and Femto-LASIK are effective and safe in correcting myopia. In this study PRK induced more spherical and higher order aberrations than Femto-LASIK.

Flexible toric iris claw phakic intraocular lens implantation for myopia and astigmatism.

PURPOSE: To assess the visual and refractive outcomes of flexible toric iris claw phakic intraocular lens implantation for correction of moderate to high myopia with astigmatism. METHODS: In this non-randomized prospective study, 31 eyes of 18 patients including 8 male and 10 female subjects with mean age of 27.62±5.53 (range 19 to 38) years with moderate to high myopia and astigmatism underwent toric Artiflex (Ophtec BV, Groningen, Netherlands) phakic intraocular lens (PIOL) implantation. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were measured in logarithm of minimum angle of resolution (logMAR) notations. Manifest refraction, safety, efficacy, predictability and complications were measured 6 months after surgery. RESULTS: Pre-operatively, mean spherical equivalent (SE) refractive error was -9.68±1.92 (range -14.00 to -6.00) diopter (D) and mean cylinder was -2.79±1.06 (range -4.75 to -1.00) D. After a minimum of 6 months, mean SE was -0.38±0.27 (range -0.87 to 0.00) D and mean cylinder was -0.66±0.43 (range -1.50 to 0.00) D. SE was within 0.50 D of emmetropia in 63.8% and within 1.0 D of target refraction in 100% of eyes. UDVA was equal or better than 20/20 in 45.1% of eyes while CDVA was equal or better than 20/20 in 67.7%; 83.8% of eyes gained 1 or more Snellen lines of CDVA after surgery. No serious complications occurred in this series of cases. CONCLUSIONS: Implantation of the toric Artiflex PIOL is a safe and effective procedure for correction of moderate to high myopia with astigmatism.

Visual outcomes of topography-guided excimer laser surgery for treatment of patients with irregular astigmatism.

The aim of this study was to evaluate the efficacy, safety, and predictability of topography-guided treatments to enhance refractive status following other corneal surgical procedures. In a prospective case series study, 28 consecutive eyes of 26 patients with irregular astigmatism after radial keratotomy, corneal transplant, small hyperopic and myopic excimer laser optical zones, and corneal scars were operated. Laser-assisted in situ keratomileusis (LASIK) (n = 8) and photorefractive keratectomy (PRK) (n = 20) were performed using the ALLEGRETTO WAVE excimer laser and topography-guided customized ablation treatment software. Preoperative and postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest and cycloplegic refraction, and corneal topography with asphericity were analyzed in 12 months follow-up. Uncorrected visual acuity (UCVA) changed from 0.2 ± 0.2 or (20/100 ± 20/100) to 0.51 ± 0.31 or (20/40 ± 20/60) in the LASIK group (P = 0.01) and from 0.34 ± 0.16 or (20/60 ± 20/120) to 0.5 ± 0.23 or (20/40 ± 20/80) in the PRK group (P = 0.01). Refractive cylinder decreased from -3.2 ± 0.84 diopters (D) to -2.06 ± 0.42 D in the LASIK group (P = 0.07) and from -2.25 ± 0.39 D to -1.5 ± 0.23 D in the PRK group (P = 0.008). Best corrected visual acuity did not change significantly in either group. Topography-guided treatment is effective in correcting the irregular astigmatism after refractive surgery. Topography-guided PRK can significantly reduce irregular astigmatism and increase the UCVA and BCVA.

Visual outcomes of Femto-LASIK for correction of residual refractive error after corneal graft.

PURPOSE: To evaluate the outcomes of the Femto-LASIK method in the treatment of refractive errors following penetrating keratoplasty (PK) at the Persian Eye Clinic, Isfahan, Iran METHODS: In a prospective, non-comparative case series, 34 consecutive symptomatic eyes of 34 patients after corneal graft, were operated on. Tissue-saving (TS) Femto-LASIK (n = 16), and Zyoptix Personalized Treatment Advanced (PTA) Femto-LASIK (n = 18) were performed using the Bausch & Lomb Technolas 217z excimer laser and Zyoptic algorithm. Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest refraction, contrast sensitivity, and HOAs were evaluated preoperatively and 12 months after enhancement treatment. RESULTS: At 12 months, the mean preoperative myopic spherical equivalent refraction (SE) decreased from -6.50 ± 2.8 D to -1.6 ± 1.8 D, and mean hyperopic SE from +3.2 ± 2.20 D to 0.37 ± 1.2 D. The safety index was 1.42 (1.2 in the TS group and 1.5 in the PTA group). In the TS group, 100% of eyes achieved 20/80 or better UCVA and 50%, 20/40 or better and in the PTA group, 100% of eyes achieved 20/80 or better UCVA and 77.7%, 20/40 or better. The efficacy index was 1.08 (0.9 in TS group and 1.21 in the PTA group). Patients obtained statistically significant lower values of root mean square (RMS) of HOAs with spherical aberrations (p < 0.05). CONCLUSIONS: Femto-LASIK method with Zyoptic programs after PK was safe, effective, and predictable for correction of spherical and cylindrical components of the refractive error.